my high school freshman son is trying to finish his homework and this one is throwing us. We know the equation of M=DxV, but how do you figure out the mass and volume of your own body? Do you think it's possible to figure this out or is it a trick question? Or maybe we're very bad at math. Anyway, we would really appreciate a serious answer. Thanks!
2006-09-17 16:17:01 · 8 answers · asked by mom of boys 1 in Science & Mathematics ➔ Mathematics
Mass is a simple conversion from weight in pounds as first answerer stated. You can do volume by displacement, although most homes wouldn't have the equipment to do this accurately. Double check that the question is really asking you to do this, not "make an estimate" or "describe" or something. If so, try to find a container large enough to completely immerse yourself in (rectangular is best for ease of calculation!) that has equal cross-sections (if you slice through it horozintally, you'd get the same shape.) A small hot tub *might* work, a large storage tote, garbage can or even a bathtub could do in a pinch. Fill the container partially with water (mae a mark indicating where the water level is), have your son step in and completely immerse himself slowly. If possible, make sure he gets as much air out of his lungs as possible, and stays still under water while you measure the change in the water level. Multiply the height by the area of the container, and you have a reasonable estimate of his volume.
Unfortunately, it probably won't work very well, since most people don't have containers well-suited to this lying around, the water is not perfectly still, the volume of displaced water is hard to calculate accurately...
Good luck anyway though!
2006-09-17 16:31:02 · answer #1 · answered by selsnick 2 · 0⤊ 0⤋
Ooh... this is a trick question...
This is how I would turn in my answer...
" I would use a device to measure the amount of displaced water by my body to give me my volume.
I would then measure my mass.
Knowing D=M/V, this would determine my body's density."
Can't go wrong with that... but other methods are:
1) Integral Calculus
2) Displacement of Water
3) Knowing the average volume of your son's body shape
or it's better just to know the human body is ABOUT the same Density as water..
We have to assume the teacher will only ask for things which can be done in a practical fashion by a freshman in H.S.
So 1 and 2 are out of the question...
Therefore, we know water has a Density of 1 g/cm^3
also know the conversion of lbs to kg is about 2.2 kg to 1 lbs
Use D = M/V and solve for Volume and you have an entire equation.
2006-09-17 16:42:16 · answer #2 · answered by rocketscienceisez 2 · 0⤊ 1⤋
Mass is easy, Take your weight in pounds and divide by 2.2; this will give your appx mass in kilograms.
As for volume, thats a bit tougher... you can get an estimate by assuming you are a series of boxes. Or my favorite, slightly fill a tub of water enough such that your body is completely covered and get in, mark the new water level along with the old water level; the amount of water it takes to fill the tub from the low line to the full line is your volume.
2006-09-17 16:24:06 · answer #3 · answered by piercesk1 4 · 0⤊ 0⤋
These two problems are an exercise in conversions. First Question: With a density of 0.92 grams per cubic centimeter, a one cubic meter block of ice will have a mass of 920000 grams, which is 920 kilograms. I arrived at this conclusion by multiplying the density by the appropriate conversion factor. I then multiplied the answer by 0.001 to convert the answer to kilograms since there are 1000 grams in one kilogram. Here is the problem: (0.92 g/cm^3) * (1,000,000 cm^3/1 m^3) = 920,000 grams. (920,000 g) * (1 kg/1000 g) = 920 kilograms. Second Question: With a density of 1.025 grams per milliliter, one liter of seawater will have a mass of 1025 grams, which is 1.025 kilograms. We can apply the same logic as above to arrive at this conclusion. Here is the problem: (1.025 g/mL) * (1000 mL/1 L) = 1025 grams (1025 g) * (1 kg/1000 g) = 1.025 kilograms I hope this has helped you.
2016-03-27 06:37:04 · answer #4 · answered by ? 4 · 0⤊ 0⤋
Assuming that you are finding "average" density of your body, since the density would vary throughout.
Mass - weigh yourself
Volume - assume your body is made out of cylinders (ie: arms are two cylinders, legs are 2 cylinders), spheres (head), and rectangular prisms (trunk). You could estimate your volume by measuring lengths, widths, diameters, etc and using common formulas to calculate volumes of the parts. Then add them together.
2006-09-17 16:26:47 · answer #5 · answered by whatthe 3 · 0⤊ 0⤋
Keeping it simple for a rough estimate, when you see somebody floating in the water, roughly what proportion of his body volume is out of the water? If you think 50%, his density must be half that of water. If you think 20%, his density would be 80% that of water. I think about 10%, so his density is 90% that of water. If he sinks, his density is more than that of water - sorry about that.
2006-09-18 00:12:54 · answer #6 · answered by Anonymous · 0⤊ 0⤋
mas divide volume =s density
2006-09-17 16:22:01 · answer #7 · answered by wizard 4 · 0⤊ 1⤋
mass=in kg (note: 2.2lb=1kg)
not sure about the volume though...
That sure is a strange question...
2006-09-17 16:20:10 · answer #8 · answered by Travis 4 · 0⤊ 1⤋